Observations on the injury mechanism of anterior cruciate ligament tears in skiers.

The purpose of this study was to demonstrate the uniqueness of the injury mechanism for acute complete tears of the anterior cruciate ligament in recreational alpine skiers by using patterns of osseous injury as detected by magnetic resonance imaging. We treated 42 patients (average age, 32 years) who met the following criteria: 1) acute complete anterior cruciate ligament tear incurred during skiing, 2) no history of knee injury, 3) magnetic resonance imaging within 30 days of injury, and 4) arthroscopy and anterior cruciate ligament reconstruction or both for documentation of all intraarticular injury. An osseous injury detected by magnetic resonance imaging was seen in the lateral femoral condyle in 17 (40%) of the patients and was located over the terminal sulcus in 15 of these patients; only 1 had arthroscopic evidence of chondral injury. Four (10%) of the 42 patients had a bone bruise on the medial femoral condyle; all were located at the extreme posterior margin. Thirty-four patients (81%) had a bone bruise on the lateral tibial plateau; 33 were located at the extreme posterior margin and 27 of these were at the posterolateral tibial rim. Twelve patients (29%) had a bone bruise on the medial tibial plateau; all were located on the posterior margin.